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UnionSine

UnionSine 4TB Ultra Slim Portable External Hard Drive

★★★★★4.4 (2111 reviews)

A pocketable 4TB portable drive that pairs a slim, non-slip redesigned shell with USB 3.0 read speeds rated up to 125MB/s

$203.71*
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*Price sourced from Amazon.com. Last updated:Aug 03, 2026.Price and availability are subject to change.

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Overview

The UnionSine 4TB Ultra Slim external hard drive is built around a simple pitch: a lot of storage in a package small enough to slip into a pocket. This upgraded version refines the shell with a mirror logo strip set against a striped non-slip pattern, and the strips double as a heat-dissipation feature meant to keep transfers stable. Rounded corners improve the hold. It is aimed at anyone who needs to move a big library of photos, video, or project files between machines without hauling a bulky desktop drive, and the 4TB capacity gives that use case real headroom.

On the practical side, the drive connects over USB 3.0 with USB 2.0 backward compatibility, and UnionSine lists theoretical speeds of up to 125MB/s reading and 103MB/s writing. A JMicron 578 controller is credited for quiet operation, while the internal chip sits inside an aluminum anti-interference layer intended to help cooling and safeguard data. Ownership is meant to be effortless: there is no software to install, so you plug it in and go. The box includes the drive, a USB 3.0 cable, and a manual, presented in gift-style packaging, and UnionSine backs it with a three-year warranty and free technical support.

Key Features

【Upgraded version】 - The mirror logo strip is combined with the striped non-slip design. The rounded corners of the shell are more suitable for holding. The strips play a heat dissipation function to ensure a stable and fast transmission process.

【Ultra-thin and quiet】 - The motherboard adopts JMicron 578 noise-free solution, giving you a quiet working environment. Lightweight and portable size designed to fit in your pocket for easy portability.

【Ultra-Fast Data Transfers】 - The external Hard Drive is used in conjunction with USB 3.0 and USB 2.0 ports to provide ultra-fast transfer speed. The theoretical read speed is up to 125MB/s, and the write speed is up to 103MB/s.

【Plug and Play】 - With no software to install, just plug it in and the drive is ready to use.The hard disk chip is wrapped with an aluminum anti-interference layer to increase heat dissipation and protect data.

【What You Get】 - 1 x Portable Hard Drive, 1 x USB 3.0 Cable, 1 x User Manual, Gift-type shell packaging ,Three-year manufacturer's warranty and free technical support services.

Specifications

Brand
UnionSine
Manufacturer
Unionsine
Capacity
4TB
Drive Type
Portable External HDD
Interface
USB 3.0 (USB 2.0 compatible)
Controller
JMicron 578
Theoretical Read Speed
Up to 125MB/s
Theoretical Write Speed
Up to 103MB/s
Setup
Plug and play, no software required
Design
Ultra-slim with striped non-slip shell
In the Box
Hard drive, USB 3.0 cable, user manual
Warranty
Three-year manufacturer warranty

Frequently Asked Questions

UnionSine rates it at up to 125MB/s read and 103MB/s write over USB 3.0. Those are theoretical interface maximums, so real-world sustained speeds on a mechanical HDD will typically be lower.
No. It is plug and play, so you simply connect it and it is ready to use with no software to install, which keeps setup quick and hassle-free.
Yes. The drive uses USB 3.0 but is backward compatible with USB 2.0 ports, though you will see the faster rated speeds only when connected to a USB 3.0 port.
It uses a JMicron 578 controller marketed as a noise-free solution for quiet operation, and the chip sits in an aluminum anti-interference layer with shell strips that aid heat dissipation.
You get the portable hard drive, a USB 3.0 cable, and a user manual in gift-style packaging, backed by a three-year manufacturer warranty with free technical support.
Yes. It is described as ultra-thin and lightweight with a pocket-friendly size, and the upgraded non-slip shell with rounded corners is designed to be comfortable to hold and carry.

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